There are many classification methods of stainless steel materials: austenite, martensite, ferrite and dual phase structure; There are chromium and chromium nickel stainless steels in chemical composition; According to the use function, it can be divided into high-strength type, low-temperature type, free cutting type, non-magnetic type and so on.
Excellent mechanical properties, corrosion resistance and high cost performance are the advantages of martensitic stainless steel, so it is widely used in manufacturing parts. Its performance can change with the temperature change, and it is often used in temperature sensitive environments, such as steam impellers, gas valves, pressure vessels, offshore oil production platforms, etc. In terms of the element content of martensitic stainless steel, generally, the Cr content is between 12wt.% – 18wt.%, and the C content is generally greater than 0.1%, because its structure is martensitic after quenching and strengthening, which makes this steel “self hardening”.
| China GB / t20878-2007 | Ｃ(wt.%) | Cr(wt.%) | American AISI | Germany DIN | Japan JIS | France NF |
| 06Cr13 | ≤0.08 | 11.5-13.5 | S41000 | X7Cr13 | SUS410S | Z6C13 |
| 12Cr13 | ≤0.15 | 11.5-13.5 | 410 | X10Cr13 | SUS410 | Z12C13 |
| 20Cr13 | 0.16-0.25 | 12-14 | 420 | X20Cr13 | SUS420J1 | Z20C13 |
| 30Cr13 | 0.26-0.35 | 12-14 | — | — | SUS420J2 | — |
| 40Cr13 | 0.36-0.45 | 12-14 | — | X40Cr13 | SUS420J2 | Z40C13 |
As a typical martensitic stainless steel, 2Crl3 has a good balance between mechanical properties and production costs, so it has a high cost performance ratio and a wide application environment. According to GBM 0 878-2007 and similar steel standards of other countries. The table shows the grade and composition content of each Crl3 type steel.
20crl3 is 2Crl3, which is a new brand expression, but we are still used to calling it 2Crl3. The chromium content of Crl3 steel is basically the same. In order to meet the corrosion resistance of this group of steels, the Cr content is specified to be 11.5-14%. The corrosion resistance of Crl3 series is different due to the difference in carbon content, But they are all in a horizontal range.
2Cr13 type stainless steel belongs to the type with low carbon content in Crl3, which has a good balance between strength and initial property. It is used for many corrosion-resistant structural parts. 3ch3 and 4Crl3 type steels are mostly used for wear-resistant parts due to the high C content. Under the heat treatment process, 2Crl3 can realize the phase change of heating and cooling by virtue of the stable austenite effect of C element. The eutectoid of austenite and the austenitization of ferrite make α- Y are transformed with each other, and under the critical cooling rate, the γ- Under the action of Cr element, the critical cooling rate of M transformation does not need to be very high. Even if air cooling is used, martensite phase will be generated. However, in order to obtain a large amount of martensite, fast cooling mode should be adopted. These characteristics make 2Crl3 have better microstructure and mechanical properties after heat treatment. It is worth noting that the carbon content of this group of steels is different, resulting in certain differences in the structure produced by cooling after austenitizing. Generally speaking, they are all martensitic stainless steels. However, if the carbon content is low, for example, 0crl3 is martensite and ferrite after austenitizing and cooling, because the carbon in phase a cannot be completely saturated, However, for 4Crl3 with high carbon content, the generated structure is martensite and carbide. Because the austenitizing temperature cannot make the carbide completely dissolve, there is a certain amount of residue, while 2Crl3 is an orthodox martensitic stainless steel.